Epidemiology of Leishmaniosis in the Nature Reserve Ofsierra Dearacena and Picos De Aroche (Southwest Spain)
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Research and Reviews ill Parasitology. 60 (3-4): 113-119 (2000) Published by A.P.E. © 2000 Asociaci6n de Parasit61ogos Espafioles (A.P.E.) Printed in Barcelona. Spain EPIDEMIOLOGY OF LEISHMANIOSIS IN THE NATURE RESERVE OFSIERRA DEARACENA AND PICOS DE AROCHE (SOUTHWEST SPAIN) i 2 3 3 i J.A. LEPE , J.M. UBEDA , F. MORILLAS , D.e. GUEVARAZ, J. MARTIN-SANCHEZ , F.J. GUERRERO , M.C. SANCHIS-MARI~ & R. PEREAI J Hospital General de Riotinto, Riotinto, Huelva, Spain 20epartamento de Microbiologia y Parasitologia, Facultad de Farmacia, Universidad de Sevilla, Cl Pro! Garcia Gonzale: sin .. 41012 Sevilla, Spain 30eparramento de Parasitologia, Facultad de Farmacia, Universidad de Granada, Campus La Carruja, 18011 Granada, Spain "Departamento de Biologia Animal, Facultad de Ciencias Experimentales, Universidad de Almeria, Almeria, Spain Received 25 May 1999; accepted 17 November 1999 REFERENCE:LEPE(J.A.), UBEDA(J.M.), MORILLAS(F.). GUEVARA(D.C.), MARllN-SANCHEJZ( .), GUERRERO.(FJ.), SANCI-Us-MARIM.CN( .) & PE· REA(R.), 2000.- Epidemiology of leishmaniosis in the Nature Reserve of Sierra de Aracena and Picos de Aroche (Southwest Spain). Research and Reviews in Parasitology, 60 (3-4): 113-119. ABSTRACT:An eco-epiderniological study of leishmaniosis was carried out in the Nature Reserve of Sierra de Aracena and Picos de Aroche, situa- ted in the north of the province of Huelva (southwest Spain). This survey includes a study of the vector, the canine reservoir and the rate of Leish- mania-human contact in the area. Of the sandtly species of proven vectorial capacity, the most abundant was Phlebotomus perniciosus (90,36%) fo- llowed by Phlebotomus ariasi (9,43%). The populations of both species develop over the year according to a typical diphasic curve. A serologic study using lndirect Fluorescent Antibody Test on 702 dogs revealed 47 with a titer ~160 (seroprevalence of 6,7%). Performing a parasitological study on several dogs with a titer ~80 and using electrophoresis analysis of isoenzymes, Leishmania infantum was isolated and identified as respon- sible for the disease. To determine the rate of human contact with Leishmania, the Montenegro skin test was used. Of 413 people tested, 12 were positive (2,9%). This result is not in agreement with the close correlation between canine leishmaniosis and positive Montenegro skin test reported by other authors in the south of Spain. This is probably due to the special relationship between the canine reservoir and human host found in this na- ture reserve, where packs of dogs are kept in kennels well away from houses, and dogs are put down at the first sign of disease, even when unspeci- fic. Furthermore, there are never, or very rarely, houses with stables for working animals, thus avoiding breeding grounds for the vector near hu- mans. KEYWORDS:Seroprevalence, canine leishmaniosis, leishmanin skin test, sandtlies, Southwest Spain. INTRODUCTION be a potential risk zone for the development of leishma- niosis (MARTINEZ-ORTEGA & CONESA, 1989). Leishmaniosis is a disease caused by different species of flagellates of the Leishmania Ross, 1903 genus. This disease has different clinical aspects and its epidemiologi- MATERIAL ANDMETHODS cal patterns are diverse. The World Health Organization considers leishmaniosis as the tenth parasitic infection in Area of study: The Nature Reserve of Sierra de Aracena and Picos the world. Its morbidity was estimated at 1.200.000 cases de Aroche is situated in the southwest of Spain, in the western part of Andalusia, and occupies all the north of the province of Huelva per year and its mortality at about one per 1000 cases (Fig. I). It has an area of 186000 hectares and has a population of (WHO, 1984). These data, however, should be reasses- 44334, the density being 15 inhabitants/km" The ratio between sed, since the outbreak of AIDS has brought about a con- men and women is about 1:I. siderable increase in mortality, owing to the fact that 2% From a bioclirnatic point of view, the Nature Reserve is found in of AIDS patients present clinical leishmaniosis (WHO, a IV(V) bioclimatic zone (RJvAs-MARTl EZ, 1988), which corres- 1991). More recent studies emphasize the importance of ponds to a sub-humid Mediterranean climate with an Atlantic in- the coinfection Leishmania-HIV, as it is frequent to find fluence. The mean temperatures range between 13° and 15° C. There is a dry season from June to the end of September and a wet 10% of parasitism in HIV positive patients in Spain (ME- season from October to March, with the heaviest rainfall in De- DRANO et al., 1992). cember and January. This paper is an attempt to get to know the epidemio- logy of leishmaniosis in an area unstudied until now. Study of the vector: Sandfly specimens were captured with sticky This nature reserve is interesting for the study of this di- tape traps during one year in ten stations spread over the Nature sease because there are a great many important packs of Reserve in order to determine the existing species, their density (number of specimens/m? of trap), abundance (number of speci- hunting dogs, and this nature reserve lies in a type IV mens of a species in relation to the total), frequency (number of bioclimatic zone (meso-Mediterranean areas with vege- stations in which a given species has been captured in relation to tation comprising forests of cork-oaks, holm-oaks and the total number of stations) and phenology. Furthermore, a survey leshew Pistacia lentiscus), all of which are considered to was carried out using (eDC) light traps through the years 1995, 114 J.A. LEPE et al. ......... ......... : " . .' SPAIN NATURE RESERVE 2• Fig. 1.- The Nature Reserve of Sierra de Aracena and Picos de Aroche. I = Aracena; 2 = Jabuguillo; 3 = Higuera de la Sierra. 1996 and 1997 in order to determine the percentage of sandflies (1992) and the formula developed by DYE (1992) and DYE et al. parasitised by Leishmania sp. (1993) for a homogeneous canine population (all dogs in similar The captured sandflies were classified according to «ad hoc» epidemiological conditions). This model requires a focus where keys (GIL COLLADO,MORILLAS-MARQUEZ& SANCHIS-MARIN, the percentage of infected sandflies is insignificant. In these condi- 1989; GALLEGO-BERENGUEetR al., 1992) and were dissected follo- tions Ro = SO", and SO is the rate of susceptible dogs (negative). wing the Rroux et at. (1986) technique. Parasitological study of dogs: ine dogs with positive serology Serological study of dogs: A randomized study of 702 dogs be- to L. infantum and with titers ranging from 80 to 10240 were selec- longing to packs of hunting hounds was performed. Samples were ted for parasitological study. Nine popliteus ganglion biopsies and obtained from cephalic vein and tested by IFAT. An antigen of the two skin biopsies were made. The puncture of the popliteus gan- Leishmania infantum Nicolle, 1909 strain MCANlES/9OIDP204 glion was performed with needle and syringe after disinfecting the was used at a concentration of 2 X 106 promastigotes/ml. Titres of skin. The skin biopsies were made on the dermatitis areas with the 20,40, 80, and 160 were taken into account. Sera with a titer 20 help of a 4 mm biopsy punch after disinfecting the area. In both ca- were considered seropositive and only titres ~16O were used to de- ses the samples were treated with a solution of sodic Penicillin G termine the seroprevalence. and later inoculated in a NNN medium, which was supplemented The Basic Reproduction Number (Ro) was determined follo- with fetal bovine serum and liquid Evans Modified Tobie's Me- wing the mathematical model of HASIBEDER,DYE & CARPENTIER dium (EMTM). Leishmaniosis in the province of Huelva (Spain) 115 Species Male Female Total Abundance Frequency Phlebotomus perniciosus 1925 184 2109 48,9% 10110 Sergentomyia minuta 969 1013 1982 45,9% lOll 0 Phlebotomus ariasi 209 11 220 5,1% 8/10 Phlebotomus sergenti 2 I 3 0,06% 3/10 Phlebotomus papatasi 2 0 2 0,04% 1/10 Total 3107 1209 4316 Table 1.- Sandflies captured. Study of the human population using the Montenegro skin P. perniciosus P. ariasi test: In order to determine the incidence of contact between L. in- Date Specimens/m! Specimens/m' fantum and the human population in the Nature Reserve, a study of cellular immunity was carried out using the Montenegro skin test April, 14th 0,1 (leishmanin skin test) (WHO, 1984). Authorised by the Delega- April, 25th ci6n Provincial del Servicio Andaluz de Salud, a survey was ca- May, 15th 0,7 0,2 rried out on 413 people (256 children and 157 adults), which is May, 31th 0,2 about 1% of the population. All children required written consent June, 14th 9,9 0,2 from their parents to be enrolled. June, 30th 28,9 1,1 The skin test was made using a Dermojet® and 0,1 ml of leish- July, 12th 27,3 2,0 manin was inoculated in the upper arm. The test was examined at July, 30th 9,1 0,6 48 hours. Indurations of mm or more were considered positive 5 Aug., 15th 9,5 0,3 (ACEDO-SANCHEZ et al., 1996). Aug., 30th 12,2 1,5 Sept., 13th 13,9 0,3 Retrospective study of leishmaniosis cases: In order to know the Sept.,30th 42,7 1,3 incidence of the disease in the area, all the clinical histories of the Oct., 15th 28,0 5,8 last ten years (1987-1997) from the Hospital General de Riotinto, o«., 30th 10,1 3,1 as well as clinical histories of the patients from the Dermatology Nov., 14th 0,6 1,0 Department of our reference hospital in the city of Huelva, were Nov., 30th 0,2 reviewed.